Evaluating the Neuromodulatory Effect of Ketamine in Long COVID-19

Participants in this arm will receive four intramuscular (IM) ketamine injections over a two-week period. The initial dose will be 0.5 mg/kg during the first session, increasing to 0.65 mg/kg in the second session, and 0.75 mg/kg for the third and fourth sessions. Injections will be administered at least three days apart.